Generally, classification is performed by predicting categorical distributions, and encouraging sharpness in the distribution in order to select the correct class [1]}. We leverage classification to encourage a single correct depth bin when supervising the depth distribution network, using the focal loss [2]}:
\(L_{\mathrm {depth}}=\frac{1}{W_F \cdot H_F}\sum _{u=1}^{W_F}\sum _{v=1}^{H_F}\mathrm {FL}(\mathbf {D}(u, v), \mathbf {\hat{D}}(u, v))\) 
